The invention relates to a rotating transformer, comprising a rotor core in the form of a circular ferromagnetic disc which is rotatable about its axis, and a stator core in the form of a circular, stationary ferromagnetic disc which is coaxial with the rotor core. The facing main surfaces of the discs have a pattern of grooves which are separated from one another by ridges, which pattern is concentric with respect to the common axis. Rotor windings and stator windings are accommodated in respective grooves, the arrangement being such that each time a rotor winding faces a cooperating stator winding, the stator windings are electrically connected to an electronic circuit outside the grooves.
Rotating transformers of this kind are used inter alia in apparatus for the recording and playback of pictures (video recorders). An example of such a device is described in U.S. Pat. No. 4,497,004. In the known rotating transformers, the rotor and stator windings consist of coils wound from copper wire and subsequently arranged in the grooves in which they are secured, for example by means of glue. The number of coils depends on the number of read and write heads present in the video recorder, because the rotating transformer constitutes the link between the (rotating) read and write heads on the one side and the stationary signal processing circuits on the other side. Because development in video recorders tends towards apparatus comprising ever larger numbers of read and write heads, the number of coils to be included in the rotating transformer also increases. This leads to manufacturing problems and costs because the gluing of the coils in the grooves on the one hand and the connection of the loose connection wires of the stator coils to the associated electronic circuits on the other hand is difficult and time consuming.